Cast-metal pipe and method of making the same



Patented July 1930 ,i

I umrwsmrrs ATENT 1 DANIEL HA vEr'MELooHEgorjNEw,roan, Y., AssIGnoit am ie m moa COMPANY, orjnnw YORK-LN; -n-conronarron or NEWI E SEY,

casrvrnranrrrn am METHOD'OF MAKING THE SAME No Drawing. Application f led May: 17,, My invention relates to new and useful im provements incast metal'pipe and a method of making the same, and more particularly contemplates as a new article of manufacture e a cast iron pipe having pronounced features of novelty over any previous cast iron pipeof which I am aware, and which will be c'apable of being machined, cut, or threaded in a manner and to an extent which was impossible in cast iron pipe hitherto known;

It is wellknown that cast iron pipeas' made previous to my invention, was hard and brittle, comparatively easy offracture, and,

method or processior producing a cast iron therefore, could not be machined, c'ut,or threaded by ordinary pipe cutting or thread-Q ing' tools. Furthermore, castfiron pipe as previously known, being hardandbrittle as compared tosteel and wrought iron'pipe, was not capable of being cut tolength'or threaded with standard tools in order to rein der the same capable of use with ordinary threaded couplings such as -are commonly used to oin lengths of steel orwrought iron pipe, and it was necessary eitherto employ packed joint coupling elements made separate from the pipe, or cast the elements of such couplings integral with the pipe. vIt was also necessaryto cast the" pipe with a metal line or wall which was thicker, as compared with steel and wrought iron pipe, in order to give the cast pipe suliicient strength i to withstand" fracture which mi ht result from bursting or tensile transverse breaks ing strains. The cast iron pipe as previously known, had little or no resiliency. transverse to its longitudinal: axis, as comparedto steel or wrought iron pipe, and therefore'was, lia ble to break when subjected to transverse bending strains or deflections. v Itis thereto-re oneof the objects ofmyinvention to provide a cast iron pip'e having characteristics whichwill rende .it capable V further object is to provide' a iron pipe which will have a metal line substan of being readily maehinable, or out, or threaded by standard tools such as are ordi narlly employed inthe cuttlng or threadlng;

I u or steel or wrought 11011' pipe.

'tially the same-as commercial steel or wrought iron. pipe of a corresponding outsidedianr I life in use as compared with ordinary known 1928. Seria1 No,278;626. I

eter, and which will withstand transverse or bursting strains far in excess of heretofore known cast iron pipe,anfdto an extent favorably comparable with steel and wrought iron plr n A further object is to provide a cast iron pipe having characteristics attaining'the' objects above mentionechwhich will withstand erosion or corrosion efi'ects and be; of long ay. t

wroughtiron pipe. v r v 1, further object is-to provide a novel Total carbons I 7.20m so Iron substantially the balanceto make' l00 s i .10. to Chromiunr understood that the analysisi ofn i the finishedcasting is preferably within the limits above given, but the rangeofpercent-:1 ages maybeslightly-above-or slightly below;

n y OII pipe and commerclal steelor jinn; a ain. 3.35 e i ,15

the maximums and minimums given, soas to bes'ubstantially .ofthe perjc entages'lgiven a nd j within proportions relatively whi ch will produce pipe having the novel characteristics ,ysisabove givenimay be produced ina oupola substantially as above given 'Thejchromiuin ahdynickelmay be' suppliedf if .desired,.'by

the useof Mayaripig-lron as a partofthe wren es; for ere M r g-ir so herein described." The auoyiron of the anal-F V containing approximately 1% of nickel and 2% of chromium, together with traces of vanadium, cobalt and titanium. In the event that Mayari pig-iron be not employed as part of the charge, I add nickel and chromium, or

elements containing the sameyinproper proportion Will be combined carbons. The per 'centage of phosphorous must he lowenough so that the metal will not be'made hard or brittle, and therefore unduly resistantto standard cutting and threading tools. By cutting and threading tools I mean suchtools as are ordinarily employed in the trades "for cuttingand threading steel or wrought iron pipe.

The charge in the c'upola 'or melting furnace is heated to'a temperature above that ordinarily employed in producing gray cast iron -for making pipe as hitherto known, which insures that graphitic carbon willbe precipitated from the molten metal to as great an extent as is practically possibleand further insures that the graphitic carbon precipitated willbe a finely divided state or minute'particles, as distinguished from the comparatively large fialrespas the same usually appear in. micrographs of ordinary gray cast iron. Preferably, the metal is heated in the cupola to such a temperature that-the metal at the spout will beat a temper t ofa p n'o:-;imately 47000 F. to 2800? E, R is well above'the spout temperatureinthe case of :ordinary gray cast iron when used for casting pipe, which normal about 2600.F..

In casting the pipe,

l. preferably; employ a suitable mold or flask structure lined with a sand mold which is dried or baked, and also use a suitable c-oreofdried or baked sand, the inside diameter of the-mold and the outside diameter of the cor being-"such as to produce pipe havingya'desired metal 5 line or wall thickness. The sand mold and the sand core are heated suitable means, for example,in a suitable oven'betore the casting is poured, v,so that the: moldan'd core will be at a temperature, of approx I'nately 400 F. when ;'the metalj'isfpoured into the mold, andthe metal is pouredinto the mold and around the corelwhileihe moltenflmetal is at a temperature of approximat'ely '2500 pouring: the metal at the temperature mentioned into Lthefheated sand mold While the latter 'isat a temperature of 400 13. approximately, the graphite or graphitic carbon in themetal w'ill be inaintained in a finely divided state or -minute particles, and the other elements in the inetal Wlll not become segregated during the pouring of the casting and during the cooling or finely divided condition in the ultimate pipe casting, and also to castthe pipe in a preliminarily heated mold in order that the precipitated graphitic carbon will be maintained in the finely divided condition or minute particles, asthis heating not only serves to reduce the percentage of combined carbons, and thereby enhance the machinab lity of the pipe, but the finely divided condition of the graphite reduces the corrodi-bility' of the casting by elements to which it may be subjectedwhen in use. The iron content of the casting which completes the "formula heretofore given, is substantially all in the form of ferrite, or its compounds, so that the pipe may be readily cut or threaded with such tools as are ordinarily employed for cutting and threading steel and wrought iron pipe, and such cutting or threading will not he attended with danger of fracture,:as is the case with hitherto known cast iron-pipe made from gray iron.

It will be noted that according to the analysis above given, the manganese is in the proportion given as a safety factor to reduce the sulphur content of the resultant iron, and prevent-any such excess oi sulphur that might tend to make the/iron brittle.

The carbon and silicon proportions as above given-are maintained so as to produce an iron which will have the desired ductility. The nickle and chromium act to accelerate the precipitation of the carbon'trom solution, the precipitation of the carbon-being, as stated above. in the torm'of graphite in a finely divided state, and-being a large proportion of the total carbons, results in acasting which will be of the desired ductility and such as may be readily cut or-threa'ded with standard tools.

Pipe mane according to my invention will be found very "resistant to corrosion and erosion. and therefore of considerablygreater life than commercial steel or wrought iron pipe 'when used under conditions which would tend to eredeor corrode the same,fer eziample,*mypipe as herein described can be satisfactorily used for acid lines of=chemic1jl plants, whether the acid 'behot, cold,--weak or concentrated, and will stand up'ii'or a long period of time, whereas commercial steel and wrought iron pipe would be"destroyed in acomparativelyshort time. liflypipe-also has long life in oil refinery systems, in acid silu e lines, contact plants:condenser beres, and -.run-down 'llllQS, where any, commercial steel or wrought iron PIPQWOLIlCl be CGIIIPHZZI tively short lived; due to erosionorcorrosion by ,theacid content of the'conveyed liquid or vapor. 1 Pipe made according to my invention may be and preferably is cast with ametalQline or wallthickn e s's substant ially the samesascommercial steel, or wrought iron pipe of the same out-side d;ameter-for example, pipe of 1.9 nches outside diameter may have am'etal line-ofsubstantialiy .20 inches pipe having an outside diameter substantially 2.375 inches may have a metal line of substantially .218 inches; pipe having an outside diameter of 2.87 5 inches may have a metal line ofsubstantially .276 inches pipe having an outs side diameter of 3.50 inches may have a metal line of .30 inches, and pipe having an out side diameter of4 inches may have ametal line of .337 inches, these metal lines being substantially the same as high quality, extra strong commercial steel or Wrought iron pipe.

Pipe made accordingto my invention will 7 have high resistance against breakage under hydraulic internal pressure. testfor example, plpe having an outside dlameter of breakage; the pipe 0f3.50 outside'diam'eter will withstand a pressure 'testof approximately-3800 pounds per square inch before breakage, and the pipe of 4.50 outside diameterxwill withstand a pressure test of ap proximately 3000 pounds per square inch before breakage, which compares favorably strength tests "with the best commercial' steel or Wrought carbonj andiron approximately sufficient to 4' I 'oomp'letethe" 100%, said" pipebeingiduotile "andfcap'able of'beingcut-"or threaded atany pbint 'alojng its" length bymeans-ot tools such ironpipe. a r i,

' The pipe will also Withstand tensile pounds or over, and isresilient inthat it 7 may be deflected to a considerable extent,

withoutibreakage, transversely .to its longi tudinal axisfor example, in the'case of the r v 119 inch outside diameter pipe mentioned and V 6 feet inlength, Will come back to perfect alinementafter at 1 inch deflection from its longitudinal axis, and such pipe will Withstand a deflection of approximately 1%.

finches before breakage; the pipe of 2.375

inches outside diameter will come back to alinement after a deflection of 1 inches,

: and-will withstand a deflection of 'l inche's before breakage; the pipe of 3.5 inches out-' side diameter can be deflected of an inch i andwill Withstand a deflection of l finches before breakage; and the pipe of 4.5 inches outside diametermay be deflectedinch and will withstanddeflection up to of an inch before breakage, it'being understood that the pipes of the outside diameters just mentioned were all'tested at a 6,,footlengthj and had the metal lines above given respec'- of approximately, 1 30,000"

ti'vly. In these are each 'ie'n r I wasjsupported 3 inches from each end, and

theiforce Was applied at the center; VThe pipe also is capable/of withstanding large,

transverse ;breaking, strains-'iior example, it i will have a transverse strength of from 3000 to; 4000' pounds arbitration bar. g V r V V The pipe also has afurther and important advantage that it may b e-cast to standard f lengths in the foundry, and' ith'er threaded whenitested by a standard I 1 at the foundry by. such tools as'are ordinarily 7 used, for threading commercial steel and 5 wrought iron pipe,or"the"lengths as cast may i I "be afterwards cutlin the field 'by ordinary] pipe cutting tools at any desired point and to a desired length,'andthen be threaded by ordinary toolsfs'uchas are employed by plumbers and'pipe'fitters. What I claim and desire to secu-re 'by ters Patent'of the United States is 1; As a newarticle of manufacture, a pipe;

'made of a' castin'g of alloy iron, which is ductile and capable of :being cut or threaded at any point initslengthby standard tools such as are employed for cuttingand threading steel and wroughtiron pipe, said'pipe also being transversely resilient substantially to the "same 'extentas steel orwrought iron pipe ofthe same dimensions, said pipe beinghighly resistant toferosion' and corrosion) 2. As a new article of manufacture,-;a cast pipe made of cast iron alloycoinprislng" sillinanganese 5% to 38%; sulphur below 11%; combined carbons 7.5% to 5%; 'graphitic .con 2.25% to'2.50%.;iphosphorus 2% to 3% lue,

carbonnotto eXceedsubstant-ially 2.75%;

.totaljcarbon s from 3.30%to 3.35% randan accelerator for precipitation of, graphitic as are used for cutting or threading steel Wroughtiron pipe, and be1ng-res1lient on its longitudinalaxis.

3; Asa-newfarti cloi manufacture'pa'cast,-

pipe made of a cast'iron alloy" comprising silicon 2.25% to 2.50% manganese-notmore than .8% phosphorus not i morethan sulphur not morev than :.1'%'; "combined carbons not more than .-6% graphiticca-rbon not 7 not; more than 3.35%;jnickel approximately 170% 415% chr omiulnapproximately 2% 5 to ;3% and iron approximately sufficient to complete the said p i-pe eingduct'ile V and capable of beingjcut or threaded at any point of its lengthby means of tools such:

' as are Qu'sed for threading and-{cutting steel or wrought iron pipe,and-beingresilienfloir.

fits longitudinal axis: a j i a .1-%' combined carbons .5 ;to.6

:.8%;; phospl1orus;. ,to 3% sulphur below graphitic carbon less than 275%.; total carbons from .3.30-%to'3.35% nickel 1% to chromi- .um ;.2-% co-3% ;.andferrite approximately sui- Lficient to completethe 100% said pipe being ductileand capable of being cut-andithreaded at any point of its length means oftools i to such as are 'nsefd if'or cuttingor threading Isteelor-wrought ironpipe,and being resilient onitslongitudinalaxis. I

5. vA..proeessofproducing cast iron pipe, Whichcast iron pipe will benductile and ca.- pable otbein out or threaded at any point in its length by-toolssuchiasare used for outtingor; threading steeloriwrought iron pipe,

wliichcomprises producing a molten iron contam ng silicon. 2.25% to. 2.50%; .manganese not more than :phosphorus not more than sulphur not: morethan 1% combinedcarbons not more than 0% graphitic carbonnot to; exceed substantially 2.75%; total carbons not more than'3.35% an accelerator for precipitation .of the raphitic carbon; and iron approximately sufficient to complete the.l00%; said molten iron being heated to a' temperature causing thepreecipitation of the graphitic carbonv in a finely divided condition and .castingthe said molten metal ina sand mold heatedto atemperature maintaining the finelydivided state of the graphitic carbon .and preventing segregation of: the elements. i

6. A process of producingcast iron pipe, which cast iron pipe will'be' ductile and cap ble of being cut or threaded at any;poin t in-its; length by toolsgsucli as are used for cutting or threading :steel or Wrought iron pipe, which comprises producing a molten iron containing-silicon .ganese not more .than ,S'%;, phosphorus not more than 3% sulphur notmore th an1i1%'; COHlblIlQCl carbons not more than .6%; graphitie. carbon not to ;exceed substantially 2.75%; totalCflrbons-not more than '3.35%; an accelerator for precipitation of the vgraphitic carbon; vandironapproximately sulficient to complete the100%1; said molten ,iron being heated to. a temperature of from .ap-

" regation'. of the. elements.

2.25% to 2.50% man-- .more than ;,sulphu rnot more than .1 combinedcarbons not. more than .6%; graphitic carbon not to exceed substantially 2.75%; total carbons not more than 3.35%,

an, accelerator :tor precipitation of the grapliitieccarbon and iron. approximately suiiicient to comp'letfe'the 100 said molten iron being heated to a temperature of from approximately 2700 F. to approximately 2800 TF1, thereby'causing the precipitation of the graphit-ic vcarbon in a finely divided condition, and. castingthe said molten metal in a sandmold heated to substantially 400? F.

to thereby maintain the finely. divided state ofthe graphitic carbon and-preventing seg- 8. A process of producing cast iron pipe,

which cast iron pipewillbe ductile and capable ofbeingcut or threaded at any point in its length by tools suchvas are used for cutting or threading steel or Wrought iron pipe,

which comprises producing a molten iron containing silicon 2.25% to 2.50%; manganese n'otmore than 8%; phosphorus not morejthan .3 0 sul )liur not more than .1 0 v 7 7 F. tothereby maintain'the finely divided state o'it'he graphitic carbon and preventing segregation of the elements. v V 1in testimony ydiereof l have hereunto s gned my name; i I

DANIEL HARVEY MELGCHEl V proximately .ZZO O F. to approximately 2800 F., thereby causing the precipitationlof the graphitie carbon in a. finely fidivided condition, ,and casting-the said molten metal in a sand mold-heatedto a temperature maintaining the finely divided: state of the graphitic carbon and preventi'ng segregation of --the elements.

.7. process in 'tslengthbytoolssuchas are-used for cut.-

I ting or threading steel or wronght ironipipe,

which comprises producinga. olten iron conta ning 1si-l con -.2.25% to 2.50% ma nga e 03 mo e tha 8z%;;=;r osp;h ru not oifg produci-ng cast: ironepipe, whlehcastirompipewillbe.ductile-and capalole ;;of.;being cut or threadedflatianypoint 

